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Date: Tue, 19 Jul 2022 02:09:58 +0200 From: andrey.konovalov@...ux.dev To: Marco Elver <elver@...gle.com>, Alexander Potapenko <glider@...gle.com> Cc: Andrey Konovalov <andreyknvl@...il.com>, Dmitry Vyukov <dvyukov@...gle.com>, Andrey Ryabinin <ryabinin.a.a@...il.com>, kasan-dev@...glegroups.com, Peter Collingbourne <pcc@...gle.com>, Evgenii Stepanov <eugenis@...gle.com>, Florian Mayer <fmayer@...gle.com>, Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org, linux-kernel@...r.kernel.org, Andrey Konovalov <andreyknvl@...gle.com> Subject: [PATCH mm v2 18/33] kasan: only define kasan_cache_create for Generic mode From: Andrey Konovalov <andreyknvl@...gle.com> Right now, kasan_cache_create() assigns SLAB_KASAN for all KASAN modes and then sets up metadata-related cache parameters for the Generic mode. SLAB_KASAN is used in two places: 1. In slab_ksize() to account for per-object metadata when calculating the size of the accessible memory within the object. 2. In slab_common.c via kasan_never_merge() to prevent merging of caches with per-object metadata. Both cases are only relevant when per-object metadata is present, which is only the case with the Generic mode. Thus, assign SLAB_KASAN and define kasan_cache_create() only for the Generic mode. Also update the SLAB_KASAN-related comment. Signed-off-by: Andrey Konovalov <andreyknvl@...gle.com> --- include/linux/kasan.h | 18 ++++++------------ include/linux/slab.h | 2 +- mm/kasan/common.c | 16 ---------------- mm/kasan/generic.c | 17 ++++++++++++++++- 4 files changed, 23 insertions(+), 30 deletions(-) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index a212c2e3f32d..d811b3d7d2a1 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -128,15 +128,6 @@ static __always_inline void kasan_unpoison_pages(struct page *page, __kasan_unpoison_pages(page, order, init); } -void __kasan_cache_create(struct kmem_cache *cache, unsigned int *size, - slab_flags_t *flags); -static __always_inline void kasan_cache_create(struct kmem_cache *cache, - unsigned int *size, slab_flags_t *flags) -{ - if (kasan_enabled()) - __kasan_cache_create(cache, size, flags); -} - void __kasan_cache_create_kmalloc(struct kmem_cache *cache); static __always_inline void kasan_cache_create_kmalloc(struct kmem_cache *cache) { @@ -260,9 +251,6 @@ static inline void kasan_poison_pages(struct page *page, unsigned int order, bool init) {} static inline void kasan_unpoison_pages(struct page *page, unsigned int order, bool init) {} -static inline void kasan_cache_create(struct kmem_cache *cache, - unsigned int *size, - slab_flags_t *flags) {} static inline void kasan_cache_create_kmalloc(struct kmem_cache *cache) {} static inline void kasan_poison_slab(struct slab *slab) {} static inline void kasan_unpoison_object_data(struct kmem_cache *cache, @@ -316,6 +304,8 @@ static inline void kasan_unpoison_task_stack(struct task_struct *task) {} size_t kasan_metadata_size(struct kmem_cache *cache); slab_flags_t kasan_never_merge(void); +void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, + slab_flags_t *flags); void kasan_cache_shrink(struct kmem_cache *cache); void kasan_cache_shutdown(struct kmem_cache *cache); @@ -334,6 +324,10 @@ static inline slab_flags_t kasan_never_merge(void) { return 0; } +/* And no cache-related metadata initialization is required. */ +static inline void kasan_cache_create(struct kmem_cache *cache, + unsigned int *size, + slab_flags_t *flags) {} static inline void kasan_cache_shrink(struct kmem_cache *cache) {} static inline void kasan_cache_shutdown(struct kmem_cache *cache) {} diff --git a/include/linux/slab.h b/include/linux/slab.h index 0fefdf528e0d..1c6b7362e82b 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -106,7 +106,7 @@ # define SLAB_ACCOUNT 0 #endif -#ifdef CONFIG_KASAN +#ifdef CONFIG_KASAN_GENERIC #define SLAB_KASAN ((slab_flags_t __force)0x08000000U) #else #define SLAB_KASAN 0 diff --git a/mm/kasan/common.c b/mm/kasan/common.c index e4ff0e4e7a9d..89aa97af876e 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -109,22 +109,6 @@ void __kasan_poison_pages(struct page *page, unsigned int order, bool init) KASAN_PAGE_FREE, init); } -void __kasan_cache_create(struct kmem_cache *cache, unsigned int *size, - slab_flags_t *flags) -{ - /* - * SLAB_KASAN is used to mark caches as ones that are sanitized by - * KASAN. Currently this flag is used in two places: - * 1. In slab_ksize() when calculating the size of the accessible - * memory within the object. - * 2. In slab_common.c to prevent merging of sanitized caches. - */ - *flags |= SLAB_KASAN; - - if (kasan_requires_meta()) - kasan_init_cache_meta(cache, size); -} - void __kasan_cache_create_kmalloc(struct kmem_cache *cache) { cache->kasan_info.is_kmalloc = true; diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index 25333bf3c99f..f6bef347de87 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -352,11 +352,26 @@ static inline unsigned int optimal_redzone(unsigned int object_size) object_size <= (1 << 16) - 1024 ? 1024 : 2048; } -void kasan_init_cache_meta(struct kmem_cache *cache, unsigned int *size) +void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, + slab_flags_t *flags) { unsigned int ok_size; unsigned int optimal_size; + if (!kasan_requires_meta()) + return; + + /* + * SLAB_KASAN is used to mark caches that are sanitized by KASAN + * and that thus have per-object metadata. + * Currently this flag is used in two places: + * 1. In slab_ksize() to account for per-object metadata when + * calculating the size of the accessible memory within the object. + * 2. In slab_common.c via kasan_never_merge() to prevent merging of + * caches with per-object metadata. + */ + *flags |= SLAB_KASAN; + ok_size = *size; /* Add alloc meta into redzone. */ -- 2.25.1
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